We examined the validity of Behar and Stringfield's Preschool Behaviour Questionnaire (PBQ) with young, elementary school age children. In Study 1, the PBQ was administered to 157 grade one children. A factor analysis was performed on the 30 items of the PBQ. The three factors that emerged were almost identical to those described by Bchar and Stringfield (hostility/aggression, anxiety/ fearfulness, and hyperactivity/distractibility) in their original investigation. In Study 2, the three grade one PBQ factors were correlated with children's scores on a social problem-solving test and on a sociometric rating scale. Rirthermore, free play observations were related with the PBQ factor scores. These Pearson product-moment correlations revealed that the PBQ factors correlated significantly with conceptually appropriate behaviours and social skills. For example, children rated as aggressive were less popular among peers, more aggressive in their play, and more likely to suggest inappropriate solutions to hypothetical social dilemmas.The study of children's peer relationships, social skills, and behaviour problems has accelerated rapidly in the past decade. Growth of interest in this area stems, in part, from research reports that the quality of children's peer relationships and early social behaviours predicts numerous social and academic outcomes in adolescence and early adulthood. For example, peer rejection and qualitatively poor peer relationships in early and middle childhood have been found to predict later school drop-out, delinquency, and mental health disorders (e.g., Cowen,